Nanoscience News (<front>)

NADPH oxidases-inspired reactive oxygen biocatalysts with electron-rich Pt sites are designed to potently amplify immune checkpoint blockade therapy. The synthesized Pt─WOx presents rapid electron transfer capability for superior reactive oxygen biocatalysis, which directly triggers endoplasmic reticulum stress, stimulates tumor-specific immune responses, and alleviates the immunosuppressive tumor microenvironment potently for amplifying the anti-PD-L1-based immune checkpoint blockade therapy.

Clinical immune checkpoint blockade (ICB)-based immunotherapy of malignant tumors only elicits durable responses in a minority of patients, primarily due to the highly immunosuppressive tumor microenvironment. Although inducing immunogenic cell death (ICD) through reactive oxygen biocatalyst represents an attractive therapeutic strategy to amplify ICB, currently reported biocatalysts encounter insurmountable challenges in achieving high ROS-generating activity to induce potent ICD. Here, inspired by the natural catalytic characteristics of NADPH oxidases, the design of efficient, robust, and electron-rich Pt-based redox centers on the non-stoichiometric W18O49 substrates (Pt─WOx) to serve as bioinspired reactive oxygen biocatalysts to potently activate the ICD, which eventually enhance cancer immune responses and amplifies the ICB-based immunotherapy is reported. These studies demonstrate that the Pt─WOx exhibits rapid electron transfer capability and can promote the formation of electron-rich and low oxophilic Pt redox centers for superior reactive oxygen biocatalysis, which enables the Pt─WOx-based inducers to trigger endoplasmic reticulum stress directly and stimulate immune responses potently for amplifying the anti-PD-L1-based ICB therapy. This bioinspired design provides a straightforward strategy to engineer efficient, robust, and electron-rich reactive oxygen biocatalysts and also opens up a new avenue to create efficient ICD inducers for primary/metastatic tumor treatments.

This study introduces cell-tethering and oxygenating colloidal hydrogels that prevent cell egression and maintain mild hypoxic conditions while providing mechanical stimulation and interconnected microporous networks. These synergistic multiple factors significantly increase the productivity of paracrine factors of mesenchymal stem cells locally and in a long-term manner, improving blood flow restoration and muscle regeneration in response to hindlimb ischemia.

Microporous hydrogels have been widely used for delivering therapeutic cells. However, several critical issues, such as the lack of control over the harsh environment they are subjected to under pathological conditions and rapid egression of cells from the hydrogels, have produced limited therapeutic outcomes. To address these critical challenges, cell-tethering and hypoxic conditioning colloidal hydrogels containing mesenchymal stem cells (MSCs) are introduced to increase the productivity of paracrine factors locally and in a long-term manner. Cell-tethering colloidal hydrogels that are composed of tyramine-conjugated gelatin prevent cells from egressing through on-cell oxidative phenolic crosslinks while providing mechanical stimulation and interconnected microporous networks to allow for host-implant interactions. Oxygenating microparticles encapsulated in tyramine-conjugated colloidal microgels continuously generated oxygen for 2 weeks with rapid diffusion, resulting in maintaining a mild hypoxic condition while MSCs consumed oxygen under severe hypoxia. Synergistically, local retention of MSCs within the mild hypoxic-conditioned and mechanically robust colloidal hydrogels significantly increased the secretion of various angiogenic cytokines and chemokines. The oxygenating colloidal hydrogels induced anti-inflammatory responses, reduced cellular apoptosis, and promoted numerous large blood vessels in vivo. Finally, mice injected with the MSC-tethered oxygenating colloidal hydrogels significantly improved blood flow restoration and muscle regeneration in a hindlimb ischemia (HLI) model.

The work introduces functional antiviral polymers that can bind to virus particles and inhibit their interaction with cells. The antiviral polymers can inhibit the cell infection irreversibly only when self-assembled into 2D supramolecular structures. Monomeric analogs of the dendritic polymer can only inhibit the virus reversibly, thus allowing for the virus to regain infectivity after dilution.

In Nature, most known objects can perform their functions only when in supramolecular self-assembled from, e.g. protein complexes and cell membranes. Here, a dendritic polymer is presented that inhibits severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with an irreversible (virucidal) mechanism only when self-assembled into a Two-dimmensional supramolecular polymer (2D-SupraPol). Monomeric analogs of the dendritic polymer can only inhibit SARS-CoV-2 reversibly, thus allowing for the virus to regain infectivity after dilution. Upon assembly, 2D-SupraPol shows a remarkable half-inhibitory concentration (IC50 30 nM) in vitro and in vivo in a Syrian Hamster model has a good efficacy. Using cryo-TEM, it is shown that the 2D-SupraPol has a controllable lateral size that can be tuned by adjusting the pH and use small angle X-ray and neutron scattering to unveil the architecture of the supramolecular assembly. This functional 2D-SupraPol, and its supramolecular architecture are proposed, as a prophylaxis nasal spray to inhibit the virus interaction with the respiratory tract.

The large-scale, high-performance WO3-x·nH2O films are prepared by the 2D black phosphorus-assisted in situ growth (TAIG) method. Record-breaking large-scale electrochromic smart windows are fabricated, exhibiting excellent electrochromic performance, including significant transmittance modulation, high coloration efficiency, and superior cyclic stability. This research marks a milestone in enhancing performance and industrial-scale production, bridging the gap to commercialization.

Electrochromic smart windows (ESWs) can significantly reduce energy consumption in buildings, but their cost-effective, large-scale production remains a challenge. In this study, the instability of black phosphorus is leveraged to induce the growth of the tungsten oxide film through its decomposition process, inspired by the 2D material-assisted in situ growth (TAIG) method. This approach results in the preparation of large-scale, high-performance WO3-x·nH2O (n < 2) films. Characterization techniques and DFT calculations confirm efficient regulation of structural water and oxygen vacancies during TAIG preparation. The WO3-x·nH2O films exhibit excellent electrochromic (EC) properties, including high transmittance modulation (74.2%@1100 nm), fast switching time (t c = 5.5 s, t b = 3.8 s), high coloration efficiency (124.7 cm2 C−1), and superior cyclic stability (transmittance modulation retained 94.7% after 20 000 cycles). Ultra-large WO3-x·nH2O film are prepared via a simple immersion process, and fabricated into a large-area ESW under facile laboratory conditions, demonstrating the economic and practical feasibility of this approach in industrial-scale production. Operated by the intelligent control circuit,  the ESW exhibits remarkable EC properties and cyclic stability This research represents a milestone in improving the performance and industrial-scale production of ESWs, bridging the gap to the commercialization of EC technology.

Multifunctional additives of potassium hydrogen phthalate (KHP) are rationally designed to achieve synergistic cationic shielding and anionic chemistry for ultrastable Zn||I2 full batteries. Electrostatic shielding K cations could construct the smooth deposition morphology effectively balancing the electric field distribution, while HP anions can reduce the activities of H2O and accelerate the charge transfer kinetics by the formation of SEI.

Electrolyte additives are investigated to resolve dendrite growth, hydrogen evolution reaction, and corrosion of Zn metal. In particular, the electrostatic shielding cationic strategy is considered an effective method to regulate deposition morphology. However, it is very difficult for such a simple cationic modification to avoid competitive hydrogen evolution reactions, corrosion, and interfacial pH fluctuations. Herein, multifunctional additives of potassium hydrogen phthalate (KHP) based on the synergistic design of cationic shielding and anionic chemistry for ultrastable Zn||I2 full batteries are demonstrated. K cations, acting as electrostatic shielding cations, constructed the smooth deposition morphology. HP anions can enter the first solvation shell of Zn2+ for the reduced activities of H2O, while they remain in the primary solvation shell and are finally involved in the formation of SEI, thus accelerating the charge transfer kinetics. Furthermore, by in situ monitoring the near-surface pH of the Zn electrode, the KHP additives can effectively inhibit the accumulation of OH− and the formation of by-products. Consequently, the symmetric cells achieve a high stripping–plating reversibility of over 4500 and 2600 h at 1.0 and 5 mA cm−2, respectively. The Zn||I2 full cells deliver an ultralong term stability of over 1400 cycles with a high-capacity retention of 78.5%.

Artificial Signaling Centers

In article number 2409731, Carsten Werner and co-workers develop a precision toolbox to modulate signaling gradients in tissue cultures. Spatial and temporal gradient control is achieved using sulfated glycosaminoglycan-based microgels (μGUIDEs) with electrostatically tunable morphogen affinity for tailored release. Individual μGUIDEs act as artificial signaling centers, locally directing vascular morphogenesis with high resolution.

Vessel Regeneration

Mesenchymal stem cells tethered to mechanically robust oxygen-generating injectable colloidal hydrogel significantly increased the secretion of various angiogenic cytokines and a chemokine that induced anti-inflammatory responses, reduced cellular apoptosis, and improved blood flow restoration and muscle regeneration in ischemic diseases. More details can be found in article number 2408488 by Mark W. Feinberg, Su Ryon Shin, and co-workers.

Bioinspired Immunoregulatory Adjuvant

In article number 2407644, Chong Cheng, Ling Ye, and co-workers introduce a bioinspired immunoregulatory adjuvant with electron-rich Pt sites and rapid electron transfer capability for superior reactive oxygen biocatalysis, which directly triggers endoplasmic reticulum stress, stimulates tumor-specific immune responses, and alleviates the immunosuppressive tumor microenvironment potently for amplifying immune checkpoint blockade therapy.

Electrochromic Smart Windows

Ultra-large-scale, high-performance electrochromic smart windows are prepared using TAIG method, which exploits the instability of black phosphorus to achieve the control of the structural water and oxygen vacancy content in WO3 films. The simplicity of TAIG makes the commercialization of smart windows to be highly accessible. More details can be found in article number 2409790 by Maofei Tian, Rongzong Zheng and Chunyang Jia.

Protocell Communication and Signaling

Polymer-based protocells equipped with artificial organelles mimic the transduction of information in retinal photoreceptors. Cellular communication involving specific organelles from different cells is taking place in response to environmental signals. Such communicating protocells open new avenues for advanced materials in medicine. More details can be found in article number 2413981 by Ben L. Feringa, Cornelia G. Palivan, and co-workers.

Osteosarcoma

The osteosarcoma postoperative therapy encountered challenges of tumor recurrence and extensive bone defects. In article number 2410589, Yufeng Zheng, Peng Wen, Dandan Xia, and co-workers report an 3D-printed biodegradable Zn-0.8Li scaffold with Gyroid unit for osteosarcoma post-surgery. After the structure design and composition selection, this scaffold exhibited favorable mechanical properties, optimally balanced the co-release of Zn2+ and Li+, thereby suppressing osteosarcoma and promoting osteogenesis.

Multifunctional Additives

Multifunctional additives of potassium hydrogen phthalate are rationally designed to achieve the synergistic cationic shielding and anionic chemistry for ultrastable Zn||I2 full batteries. K cations could construct the smooth deposition morphology, while HP anions could reduce the water activities and accelerate the charge transfer kinetics. More details can be found in article number 2411686 by Ho Seok Park and co-workers.

2D Supramolecular Nanomaterials for Virus Inhibition

In article number 2408294, Rainer Haag, Francesco Stellacci, Kai Ludwig, and their research team successfully inhibits severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with an irreversible (virucidal) mechanism with self-assembled 2D supramolecular nanomaterials, based on a dendritic polymer. The cover image illustrates a “virus like” sea mine targeting a sailing ship (human lung). The forming 2D nanomaterials catch and trap it, like a fishing net and prevent it from reaching its target.

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Surface-plasmon-resonance (SPR) typically detects in the nanomolar range. A pH-conditioning of a physisorbed biolayer, hosting trillions of capturing antibodies or probes enables SPR to detect a single protein or DNA-strand in 0.1 mL of plasma. The pH-conditioning transition the biolayer in a metastable state where a single affinity-biding event can trigger an amplification mechanism involving a broad self-propagating electrostatic rearrangement

DNA can be readily amplified through replication, enabling the detection of a single-target copy. A comparable performance for proteins in immunoassays has yet to be fully assessed. Surface-plasmon-resonance (SPR) serves as a probe capable of performing assays at concentrations typically around 10⁻⁹ molar. In this study, plasmonic single-molecule assays for both proteins and DNA are demonstrated, achieving limits-of-detections (LODs) as low as 10⁻2⁰ molar (1 ± 1 molecule in 0.1 mL), even in human serum, in 1 h. This represents an improvement in typical SPR LODs by eleven orders-of-magnitude. The single-molecule SPR assay is achieved with a millimeter-wide surface functionalized with a physisorbed biolayer comprising trillions of recognition-elements (antibodies or protein–probe complexes) which undergo an acidic or alkaline pH-conditioning. Potentiometric and surface-probing imaging experiments reveal the phenomenon underlying this extraordinary performance enhancement. The data suggest an unexplored amplification process within the biomaterial, where pH-conditioning, driving the biolayer in a metastable state, induces a self-propagating aggregation of partially misfolded proteins, following single-affinity binding. This process triggers an electrostatic rearrangement, resulting in the displacement of a charge equivalent to 1.5e per 102 recognition elements. Such findings open new opportunities for reliable SPR-based biosensing at the physical detection limits, with promising applications in point-of-care plasmonic systems.

Lattice-confined Pt1/Ni(OH)2 SACs with excellent activity for hydrogen evolution reaction (HER) are constructed by a co-reduction strategy. Mechanism studies disclose the Pt 3d orbital strongly hybridizes with O 2p and Ni 3d orbitals in Ni(OH)2, thus largely reducing the energy barrier of the rate-determining step during HER. Finally, this facile synthesis approach is extended to fabricate other 9 lattice-confined SACs.

The confining effect is essential to regulate the activity and stability of single-atom catalysts (SACs), but the universal fabrication of confined SACs is still a great challenge. Here, various lattice-confined Pt SACs supported by different carriers are constructed by a universal co-reduction approach. Notably, Pt single atoms confined in the lattice of Ni(OH)2 (Pt1/Ni(OH)2) with a high electron-deficient state exhibit excellent activity for basic hydrogen evolution reaction (HER). Specifically, Pt1/Ni(OH)2 just requires 15 mV to get 10 mA cm−2 and the mass activity of Pt1/Ni(OH)2 is 15 times of commercial Pt/C. Moreover, Pt1/Ni(OH)2 assembled in an alkaline water electrolyzer shows 1030 h durability under the industrial current density of 800 mA cm−2. In situ spectroscopy techniques reveal Pt─H and “free” OH radical can be directly observed for Pt1/Ni(OH)2, confirming the lattice-confined Pt single atoms play a key role during HER. Further density functional theory uncovers the Pt 3d orbital strongly hybridizes with O 2p and Ni 3d orbitals in Ni(OH)2, which quickly optimizes the electronic state of the Pt site, thus largely reducing the energy barrier of the rate-determining step to 0.16 eV for HER. Finally, this synthesis method is extended to construct other 9 lattice-confined SACs.

This work reports a general methodology for in situ synthesis of eight nanoMOFs which are exclusively located inside the internal mesochannels. This is the first report of the complete impregnation and even dispersion of nanoscale MOFs within the interior channels of mesoporous carbons, which can regulate Zn2+ plating electrochemistry toward stable aqueous Zn batteries.

As an alternative to bulk counterparts, metal–organic framework (MOF) nanoparticles isolated within conductive mesoporous carbon matrices are of increasing interest for electrochemical applications. Although promising, a “clean” carbon surface is generally associated with poor compatibility and weak interactions with metal/ligand precursors, which leads to the growth of MOFs with inhomogeneous particle sizes on outer pore walls. Here, a general methodology for in situ synthesis of eight nanoMOF composites within mesochannels with high dispersity and stability are reported. Mesoporous polydopamine (mesoPDA)-F127 nanospheres with unique surface chemistry, e.g., nanoconfined spaces, catechol functional groups, pyrrolic N doping, and hydrophilic PEO blocks, are found to be a suitable molecular platform. Sliced cross-sectional TEM, HAADF-STEM, and corresponding EDS elemental mapping, as well as nitrogen adsorption characterizations, are utilized to visualize the in situ growth process of ZIF-8 nanoparticles. These careful analyses provides direct evidence that the highly dispersed ZIF-8 is exclusively located inside the internal mesochannels. After moderate carbonization of the mesoPDA-F127/ZIF-8 nanocomposites, a prototype for a mesoporous carbon-isolated ZIF-8 nanostructure is achieved, which can regulate Zn2+ plating electrochemistry toward stable aqueous Zn batteries. This is the first report of the complete impregnation and even dispersion of nanoscale MOFs within the interior channels of mesoporous carbons.

A new charge loss and a voltage loss model are proposed and a historical record output energy density of 5.03 J m−2 is achieved by the effective collection of interface tribo-charges and the increase in load voltage during the charge extraction process.

The effective collection of interfacial tribo-charges and an increase in load voltage are two essential factors that improve the output energy of triboelectric nanogenerators. However, some tribo-charges are hardly collected through one or multiple integrated side electrodes based on corona discharge, and their load voltages are limited by air breakdown in adjacent electrodes. In this study, a dynamic quasi-dipole potential distribution model is proposed to systematically reveal the mechanisms of interfacial tribo-charge loss. Based on this model, an optimization route is designed to reduce the interfacial charge loss stepwise, achieving a 15-fold improvement in charge collection from the tribo-interface. A potential difference enhancement strategy is used for the first time to increase the air breakdown threshold between the inner electrodes and increase the output voltage under a large load. By effective increase in charge collection efficiency and load voltage, a historical record output energy density of 5.03 J m−2 is obtained. This study refined and optimized the interfacial charge loss mechanisms and provided advanced guidance for efficiently extracting energy during the triboelectrification process.

This review meticulously outlines the main effects of elevated temperatures on performance for polymer dielectrics and summarizes core modification strategies, while discussing the reasons for the performance difference between lab research and practical application from large-scale preparation and device design. This review may serve as a roadmap for the research and development of polymer dielectrics for years to come.

Film capacitors are widely used in advanced electrical and electronic systems. The temperature stability of polymer dielectrics plays a critical role in supporting their performance operation at elevated temperatures. For the last decade, the investigations for new polymer dielectrics with high energy storage performance at higher temperatures (>200 °C) have attracted much attention and numerous strategies have been employed. However, there is currently still a large gap between lab research and large-scale production. In this review, the main effects of high temperature on the dielectric properties are analyzed and core modification strategies are summarized. The scientific and technological reasons for the performance difference between lab research and practical application are also discussed. Further, several processes for large-scale film preparation and typical device structure design are reviewed. The current research and product launches pertaining of high-temperature film capacitors are also summarized. Conclusive insights and future perspectives are delineated to offer strategic direction for the ongoing and prospective innovation in polymer dielectric materials.